Liquid level sensors are used in tanks that house liquids, such as fuel, to determine the amount of liquid remaining in the tank. Most fuel sensors use a float that communicates the surface level of the fuel to a sensing unit. The sensing unit converts the angular position of the float into a fuel level in the tank. Common sensing units include mechanical gauges, potentiometer sensors, and magnetic position sensors. However, mechanical gauges and potentiometers can be inaccurate while magnetic sensors can degrade over time.
Compared to other magnetic position sensors, inductive sensors are more cost effective because they do not need a magnet and instead use an electromagnetic coil. Inductive sensors are also desirable to use in vehicles instead of magnetic type sensors because inductive sensors are generally more reliable. Magnetic sensors can suffer performance loss as the magnet degrades and are more sensitive to magnetic disturbances from the surrounding environment. Accordingly, it is desirable to have a sensor not dependent upon magnets and more tolerant of interference from common automotive devices such as electric motors and alternators.